BARRE — Vermont’s secretary of education has written a letter condemning the federal No Child Left Behind Act, which has identified nearly every school in the state as “low performing.”

Education Secretary Rebecca Holcombe issued a letter Wednesday to parents and caregivers of students in the state’s K-12 public school system about what she called “broken NCLB policy.” She said it forces the state to identify a school as low performing if a single student fails to reach the “proficient” level on statewide standardized tests.

“This policy does not serve the interest of Vermont schools, nor does it advance our economic or social well-being,” Holcombe wrote. “Further, it takes our focus away from other measures that give us more meaningful and useful data on school effectiveness.”

Under the federal NCLB Act of 2001, states must use a standardized test to assess student proficiency, and more importantly, adequate yearly progress, or AYP. It is this measure of progress that has labeled nearly every Vermont school as low performing.

Each year for the past 13 years, the NCLB Act has lowered the allowable percentage of students whose test results suggest they are not proficient in math or language arts. This year, that percentage became zero.

In effect, all it takes for a school to labeled as low performing is for a single student to fail to reach a score of proficient.

Most states are not facing the same dilemma because they received a waiver from the U.S. Department of Education. In exchange for the waiver, the states agreed to use standardized test results to evaluate teachers and principals.

Vermont — along with California, Montana, Nebraska and North Dakota — never applied for the waiver. As a result, nearly every school in these states has been identified as low performing.

Holcombe said Vermont did not apply for the waiver because research has shown standardized tests to be unreliable for teachers in classrooms with 15 or fewer students, which compose nearly half of the classrooms in the state.

“It would be unfair to our students to automatically fire their educators based on technically inadequate tools,” Holcombe wrote.

Some states that received waivers are having second thoughts about tying teacher performance to standardized tests.

In March, legislators in Washington state voted not to use test scores to measure teacher efficacy. In response, the U.S. Department of Education rescinded its waiver. Friday, the Utah State Board of Education was expected to decide whether it would seek a waiver extension.

Consequences for failing to meet AYP vary, depending on how many years the school has been identified as low performing. The first step is to create a corrective action plan intended, over a multi-year period, to raise test scores.

However, the NCLB Act also contains provisions for more dramatic actions, from the large-scale dismissal of school staff to closing a public school and reopening it as a charter school.

Other provisions include turning over the school to the state or to a private management company.

“Ironically, the only way a school could pass the NCLB criteria would be to leave some children behind — to exclude some of the students who come to our doors,” Holcombe wrote. “That is something public schools in Vermont will not do.”

By some metrics, Vermont’s students are doing quite well. The state has the highest graduation rate in the country, and in a 2013 study by the U.S. Department of Education that compared test scores by state against scores from 47 other nations, Vermont ranked seventh in the world in eighth-grade math and fourth in the world in eighth-grade science.

In a few short days, Holcombe’s letter has garnered national attention, including praise from the Northwest Progressive Institute, a liberal advocacy group for Idaho, Oregon and Washington. The group described the letter as a “remarkable, even inspiring document that Washington should immediately follow.”

“Vermont could have hung their heads in shame,” the group said in a statement. “Instead, they took the requirement as an opportunity to defend holistic public education and attack (U.S. Education Secretary Arne) Duncan’s test-obsessed policies.”

Dianne Ravitch, research professor of education at New York University and author of the 2011 book, “The Death and Life of the Great American School System: How Testing and Choice Are Undermining Education,” also praised Holcombe for her stand against NCLB.

“For her thoughtfulness, her integrity, her devotion to children, her understanding of the broad aims of education, and her courage in standing firm against ruinous federal policies, Rebecca Holcombe is a hero of American education,” Ravitch wrote in her blog Thursday.

“If our nation had more state commissioners like her, it would save our children from a mindless culture of test and punish that the federal department of education has imposed on them and our nation’s schools.”